Split TrafficPolicer into a generic one-way packet filter class and a policer-specific logic.

net/quic/test_tools/simulator/packet_filter.cc

Index: net/quic/test_tools/simulator/packet_filter.cc
diff --git a/net/quic/test_tools/simulator/packet_filter.cc b/net/quic/test_tools/simulator/packet_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a988d9bdd713ab9247ccd998d8363ca58eddf8fc
--- /dev/null
+++ b/net/quic/test_tools/simulator/packet_filter.cc
@@ -0,0 +1,40 @@
+// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/quic/test_tools/simulator/packet_filter.h"
+
+namespace net {
+namespace simulator {
+
+PacketFilter::PacketFilter(Simulator* simulator,
+                           std::string name,
+                           Endpoint* input)
+    : Endpoint(simulator, name), input_(input) {
+  input_->SetTxPort(this);
+}
+
+PacketFilter::~PacketFilter() {}
+
+void PacketFilter::AcceptPacket(std::unique_ptr<Packet> packet) {
+  if (FilterPacket(*packet)) {
+    output_tx_port_->AcceptPacket(std::move(packet));
+  }
+}
+
+QuicTime::Delta PacketFilter::TimeUntilAvailable() {
+  return output_tx_port_->TimeUntilAvailable();
+}
+
+void PacketFilter::Act() {}
+
+UnconstrainedPortInterface* PacketFilter::GetRxPort() {
+  return input_->GetRxPort();
+}
+
+void PacketFilter::SetTxPort(ConstrainedPortInterface* port) {
+  output_tx_port_ = port;
+}
+
+}  // namespace simulator
+}  // namespace net